This invention relates to the field of multi-positionable brushes in general, and, in particular, to bi-positionable toothbrushes.
The desirability for certain uses of a toothbrush, the bristle array of which can be moved angularly with respect to the handle has been recognized for more than a 100 years, as evidenced by U.S. Pat. No. 430,909. Since then, there have been issued numerous United States and foreign patents on toothbrushes designed with such capability. Examples are British Patent No. 191,745, issued in 1923; Austrian Patent No. 134,759, issued in 1933; French Patent No. 1,075,819, issued in 1954; German Patent No. 214,298, issued in 1960; French Patent No. 2,450,579, issued in 1979; and U.S. Pat. Nos. 4,731,896, 5,033,154, 5,003,658, 5,228,166 and 5,442,831, issued Aug. 22, 1995, to the present inventor.
The problem with the prior art devices is that they have not met all of the desired features for an angularly adjustable toothbrush. Principal among these features are: effectiveness in holding the angular position in which the toothbrush may be set; simplicity of construction and assembly and related requirement of minimizing the expense of its manufacture; convenience for the user, both from the standpoint of adjusting the angle and from the standpoint of holding the brush during the toothbrushing operation. Prior art brushes have failed adequately to meet one or more of these desirable features.
In a first embodiment of the invention an angularly adjustable toothbrush may be constructed of two moldable parts and a pin. The two parts are the rotatable brush head member and the handle. The brush head member is elongated and rigid has a predetermined length, with a forward end and an after end. The forward end supports a brush array. The brush array extends laterally from the member""s length. The after end of the member is flared and terminates in an essentially flat first surface angled with respect to a long axis of the member. This first angled surface includes a series of synmmetrical locking features. The brush head member has a first axial bore commencing at the first angled surface and which is orthogonal to the angled surface and terminates inwardly. The first axial bore is sized to closely fit a pin secured in the member.
The handle has a predetermined length, with a forward end and an after end. The forward end of the handle is flared and terminates in an essentially flat second surface angled with respect to the long axis of said handle. The second angled surface includes a series of mating symmetrical locking features configured to mate with the symmetrical locking features of the first angled surface of the brush head member. The handle has a second axial bore beginning at the second angled surface and orthogonal to the handle and terminating inwardly.
The pin has a cylindrical cross-section and has a forward end and an after end. The pin includes means for permanently securing the forward end of the pin within the first axial bore. The pin includes, at the after end, a means of being rotatably secured within the second axial bore.
In a variant of the first embodiment the handle includes finger-gripping features. In another variant of the first embodiment of the invention, the symmetrical locking features comprise one or more pairs of v-shaped grooves on the first angled surface of the brush head member and one or more pairs of mating v-shaped projections on the second angled surface of handle. The v-shaped grooves and v-shaped projections extend radially from the first and second axial bores, respectively.
In a second embodiment, the present invention may be constructed of two moldable parts, a pin, a coil spring and a retaining clip. The two parts are the rotatable brush head member and the handle. The brush head member is elongated and rigid has a predetermined length, with a forward end and an after end. The forward end supports a brush array. The brush array extends laterally from the member""s length. The after end of the member is flared and terminates in an essentially flat first surface angled at less than 90 degrees with respect to a long axis of the member. This first angled surface includes a series of symmetrical locking features. The brush head member has a first axial bore commencing at the first angled surface and which is orthogonal to the angled surface and terminates inwardly. The first axial bore is sized to closely fit a pin secured in the member.
The handle has a predetermined length, with a forward end and an after end. The forward end of the handle terminates in an essentially flat surface angled to the long axis of the handle at an angle complementary to the included angle between the angled surface of the brush head member and the long axis of the member. The sum of the two angles is approximately 180 degrees. The second angled surface includes a series of mating symmetrical locking features configured to mate with the symmetrical locking features of the first angled surface of the brush head member. The handle has a second axial bore beginning at the second angled surface and orthogonal to the second angled surface and terminating inwardly.
The pin has a cylindrical cross-section and has a forward end and an after end. The pin includes means for permanently securing the forward end of the pin within the first axial bore. The after end of the pin includes an annular groove sized to accommodate a retaining clip.
The second axial bore has an outer portion sized to slidably accommodate the cylindrical pin, a central portion sized to slidably accommodate the pin when surrounded by a coil spring, and an inner portion sized to slidably accommodate the pin. The handle includes at least one transverse opening at the central portion of the second axial bore to permit placement of the coil spring and attachment of the retaining clip. The brush head member is secured to the handle by inserting the coil spring into the central portion of the second axial bore through the transverse opening. The after end of the pin is then inserted into the second axial bore and through the coil spring, and then the retaining clip is attached to the annular groove in the after end of the pin. The coil spring is thereby compressed between the outer portion of the second axial bore and the retaining clip and thus urges the pin to withdraw into the handle.
The brush head is aligned with the handle in a first alternative angular position by pulling the brush head away from the handle until the coil spring is sufficiently compressed that the symmetrical locking features of the brush head member and the handle are disengaged from each other. The brush head member is then twisted with respect to the handle to the desired position and then released allowing the symmetrical locking features of the first angled surface of the brush head member to engage the mating symmetrical locking features of the second angled surface of the handle.
The brush head is aligned with the handle in a second alternative angular position by pulling the brush head away from the handle until the coil spring is sufficiently compressed that the symmetrical locking features of the brush head member and the handle are disengaged from each other. The brush head member is then twisted with respect to the handle approximately 180 degrees and then released allowing the symmetrical locking features of the first angled surface of the brush head member to engage the mating symmetrical locking features of the second angled surface of the handle.
When the handle is twisted to a first position and released so that the symmetrical locking features align, the resulting toothbrush will have an essentially straight configuration. When the handle again pulled partially away from the brush head member and twisted approximately 180 degrees to a second position and the handle is released so that the mating locking features align, the resulting toothbrush will have a handle offset from the brush head member. The offset angle is the difference between 180 degrees and the sum of the included angle between the long axis of the brush head member and its angled surface and the included angle between the long axis of the handle and its angled surface. For example, if the angled surfaces of the brush head member an the handle are each angled at 75 degrees to their long axes, the sum of their included angles would be 150 degrees. The difference between this sum and 180 degrees is 30 degrees, the resulting offset of the handle from the brush head member.
In a variant of the second embodiment the handle includes finger-gripping features. In another variant of the second embodiment of the invention, the symmetrical locking features comprise one or more pairs of v-shaped grooves on the first angled surface of brush and one or more pairs of mating v-shaped projections on the second angled surface of handle. The v-shaped grooves and v-shaped projections extend radially from the first and second axial bores, respectively.
It may thus be seen that the present invention provides an easily adjustable angled toothbrush of a simple design which may be fabricated of two molded parts, a pin, a coil spring and retaining clip, all of which are easily assembled.